Note: 2.2-rc.2 requires Erlang/OTP R19.3+ to build.
Bugfix and Enhancements
Compatible with Erlang/OTP R20 (emq-relx#77)
CoAP gateway plugin supports coap-style publish & subscribe pattern. (emq_coap#33)
MQTT-SN gateway plugin supports sleeping device (emq_sn#32)
Upgrade esockd and mochiweb libraries to support restarting a listener (esockd#54)